Such a multiplexing arrangement is generally known in the art and therein each of the input memory units in turn receive a data packet. If r had been equal to n, the number, say y, of digital words constituting a data packet would be a multiple of n and could thus be stored in a finite number of memory portions of an input memory unit. A standard multiplexer means could then be used to sequentially read the contents of the memory portions of a first input memory unit and transfer them to the output terminal until a complete data packet is read, and this prior to reading the memory portions of, e.g., a second input memory unit. The input memory units could thus be handled sequentially and in a cyclic way. An optimal output speed of the data packets is then obtained because the digital words of the data packets are transmitted to the output terminal in a continuous way, i.e. without gaps between two consecutive data packets.
However if n is not a sub-multiple of y, one of the memory portions, generally the last one, contains a set of only r digital words instead of n, r being the rest of the division of y by n. If the above mentioned standard multiplexer means is then used in the multiplexing arrangement, the data packets are transmitted to the output terminal with gaps of n-r digital words between two consecutive data packets. As a result, the output speed of these data packets is negatively affected.
The case where r is smaller than n is however possible in telecommunication systems where for instance Asynchronous Transfer Mode (ATM) data packets or cells of y=53 digital words of one byte each are transmitted and where the input memory units have memory portions of, e.g., n=4 digital words or bytes. In that case, each data packet requires 14 memory portions and the 14.sup.th or last memory portion contains only r=1 digital word or byte. When using the above mentioned multiplexing arrangement, the successive data packets will be separated, at the output terminal, by a gap having a length of n-r=3 digital words whereby, as already mentioned, the output speed is obviously reduced with respect to that of data packets transmitted without gaps.